In my prior U.S. Pat. No. 3,831,862, I disclosed a spray tip assembly in which the spray tip orifice is mounted in a removeable and reversible sleeve which is secured in the housing with a sliding pin interlock. This construction requires loosening of the body from its adapter to reverse the spray tip orifice.
In my prior U.S. Pat. No. 4,116,386, I disclosed a spray tip assembly in which the spray tip orifice is mounted in a cylindrical turret member which can be rotated in the housing to reverse the orifice member for cleaning. This construction employs a solid, resilient plastic seal which has a cylindrical concave face conforming to and mating with the cylindrical surface of the turret member.
A recently issued patent, U.S. Pat. No. 4,165,836, discloses that solid plastic seals experience excessive wear and suggest that an entirely metal seal be used to provide metal-to-metal contact between the seal and turret member. Experience with devices of this invention, however, reveals that the metal seal in not effective with low viscosity liquids which leak from the assembly under the high pressures used in airless spraying.
Accordingly, it is desirable to provide a spray tip with a reversible orifice having a seal construction which obviates the prior art difficulties with solid plastic seals and which, nevertheless, achieves tight sealing even with low viscosity liquids. It is also desirable that the spray tip permit a simple removal and interchanging of the spray orifice without disassembly of the other parts of the spray tip.